Does anyone know how to free them
In Queen of Hearts Court?
There are stone you move that have numbers and pictures that they are for.
You then step on the buttons under the pictures from 1 - 4 in the order they are, making sure you don't step on a button moving around to do this.
Maps and videos https://forum.pixelfederation.com/diggysadventure/t/alice-in-wonderland
In addition to what gamemaster posted above
Check out the relevant Wiki page, maps, videos, guides, walkthroughs & hidden gifts/bonuses in these links
You will generally find that the hidden gifts/bonuses are clearly marked on the maps created by Roeland which are contained in these links below